Automatic boom positioning device



May 17, 1966 w. KAMPERT ET AL 3,251,492

AUTOMATIC BOOM POSITIONING DEVICE Filed Feb. 27, 1964 2 SheetsSheet 1 INVENTORS jg [211 e124 1.7 5%14 H/fonfies 88 13 wa k y 1966 K. w. KAMPERT ET AL 3,251,492

AUTOMATIC BOOM POSITIONING DEVICE 2 Sheets-Sheet 2 Filed Feb. 27, 1964 INVENTORS java Deli JO5 QIQ ff fine/ es e 'g l.

United States Patent "ice 3,251,492 AUTOMATIC BOOM POSITIONING DEVICE Keith W. Kampert and Joseph H. Konefes, Libertyville,

Ill., assignors to The Frank G. Hough C0., a corpora- .tion of Illinois Filed Feb. 27, 1964, Ser. No. 347,715 7 Claims. (Cl. 214-140) The present invention relates to automatic positioning devices in general, and more particularly, to a device for automatically positioning the boom on a tractor loader.

The cycling time, i.e., the time it takes for the tractor loader to fill the bucket, travel to the place of deposit, dump the bucket, and return to the place for filling the bucket, is' very critical. The time required to complete a given operation has a direct bearing on the cost and thus any means which can decrease the cycle time, by even a few seconds, is highly desirable. One of the most common operations encountered is the filling of a truck or other type of vehicle. Starting with the bucket in a digging position, and therefore the boom in its lowermost position, the operator must maneuver the tractor loader by means of a steering wheel in order to properly position the tractor loader with respect to the truck. The operator must simultaneously be, raising the boom to elevate the bucket so that it will clear the side of the truck body. When the bucket is properly positioned over the truck body he then must actuate the dump cylinder to empty the bucket. Since the lift cylinders which actuate the boom and the dump cylinder which actuates the bucket are controlled by separate control levers mounted within the operators cab, it can be appreciated that there would be a slight delay as the operator moves his hand from the control lever for the boom cylinders to the control lever for the bucket cylinder. Elimination of this delay in moving the hand from one control lever to the other would obviously result in a more efficient operation of the tractor loader.

The environment under which the tractor loader is operated not only effects the cycle time, but also canbe controlling from the standpoint of safety. For example loading within a mine or where overhead clearance is limited for one reason or another, the operator must continuously attend to the control lever which operates the boom lift cylinders.

It is, therefore, an object of the present invention to provide a means for automatically stopping the boom at a given height. 7

It is'an-other object of the present invention to provide 'an automatic device for limiting the height of the boom and which is quickly and easily adjustable by the operator.

It is still another object of the present invention to provide an adjustable drive means which is simple and easy to' construct, and which is relatively inexpensive.

Various other objects and advantages will appear from the following description of one embodiment of the invention, and the novel features will 'be particularly pointed out hereinafter in connection with the following specification and drawings wherein:

FIGURE 1 is a side elevational view of a tractor loader with the invention incorporated therein;

FIGURE 2 is a side elevational view of the actuating mechanism as viewed from the interior of the operators compartment;

' FIGURE 3 is a cross-sectional view taken on line 33 of FIGURE 2; and

FIGURE 4 is a cross-sectional View of the end of the control valve for the boom showing the release mechamsm. i

3,251,482 Patented May 17, 1966 Referring now to. the drawings, there is shown in FIGURE 1 a tractor loader, indicated generally at 10, having a pair of boom arms 12 pivotally mounted on the tractor loader by means of pivot pins 14. A bucket 16 is pivotally carried on the forward ends of the boom arms 12 and is connected to a hydraulic ram 22 on the tractor loader through a yoke 20 and links 18. The hydraulic ram 22 controls the attitude of the bucket 16, in a manner well-known in the art. A pair of lift cylinders 24 are pivotally carried on the tractor loader 10 by means of pins 26 and have their rod ends 30 pivotally secured to the boom arms 12 at a point intermediate their ends by pins 28. Hydraulic fluid under pressure is directed to the head end of the hydraulic rams 24 to lift or raise the boom arms. Conversely, the boom arms are lowered by directing fluid under pressure to the rod end of the lift cylinders 24. The flow of hydraulic fluid to the respective ends of the lift cylinder 24 is controlled by the position of the spool 104 in the boom control valve 50. The position of the spool 104 is determined by the movement of the control lever 40 located in theoperators compartment 42 on the tractor loader.

A control mechanism indicated generally at is positioned Within the operators cab 42 within easy reach of the operator. The control mechanism 60, as best shown in FIGURES 2 and 3, is provided with a shaft 62 rigidly attached to the wall 43 of the cab 42. A sleeve 64 is rotatably mounted on the shaft 62 by means of bearings 66. A plate 68 is secured to the sleeve 64 and is provided with a plurality of friction members or rubber grommets 70 afiixed thereto. A knob 72 is rotatably mounted onthe shaft 62 by means of bearing 74. A substantially circular plate 86 having a camming portion 88 extending outwardly from the periphery thereof is rigidly secured to the knob '72. A central counterbore 82 is provided in the knob 72- to' accommodate a compression spring 76. The spring 76 urges the circular plate 86 into engagement with the rubber grommets 70 by acting against a washer 78 secured to the shaft 62 by means of a snap ring 80. A coverplate 84 is provided to close the opening in the knob 72. .When the circular plate 86 is urged into engagement with the rubber grommets 70 by the bias of compression spring 76, itis apparent that the rubber grommets 70 will provide a fr-iction drive between the plate 68 and the circular plate 86 having the camming portion 88, which will rotate the two plates in unison. An arm 90 is rigidly secured to the sleeve 64. A lug 94 attached to the boss of the boom arm 12 is connected to the arm 90 by means of a rigid link 92. As will be apparent by referring to FIGURE 1,

raising or lowering of the boom arms will cause rotation of the sleeve 64 through arm 90, rigid link 92 and the lug 94 secured to the boss of the boom arm.

A valve 96 having an actuating plunger 93 is attached to a bracket on the side wall 43 of the operators compartment 42 and is provided with a pivotally mounted operating arm 98 having a roller 100 thereon. The valve 96 is located relative to the circular plate 86 so that the camming portion 88 will contact the roller 100, pivot the arm 98 and depress the plunger 93 against the bias of a spring contained within the valve 96. A source of fluid under pressure, e.g., compressed air is connected to and communicates with the inlet of the valve 96.

When the operating arm 98 is pivoted, the plunger 93 will open the air valve 96 permitting fluid under pres- Sure to be directed to the end of the boom control valve 50, entering through conduit 102. The boom control valve spool 104 to a center neutral position through the action of the self-centering sleeves 108. A tubular extension 110 is formed on the end of valve spool 104. A pair of holes 111 are formed in the tubular extension 110 and are of sufficient size to accommodate the balls or detents 116. A plunger 113 is slidably mounted within the tubular extension 110 and is biased into contact with the balls or detents 116 by the compression spring 120. The portion of the plunger 118 which contacts the balls or detents 116 is provided with a camming surface 119 which urges the detents 116 outwardly through the holes 111 into contact with the casing of the control valve 50. An annular groove 112 is formed in the casing of the control valve 50 and is shaped to receive the detents 116. A captive piston 122 is reciprocably retained within a cylinder 124 formed on the end of control valve 50. The captive piston 122 is provided with an extension 126 of reduced diameter which protrudes beyond the cylinder 124. The conduit 102 is connected to the control valve 50 and communicates with the cylinder 124. When the operator desires to raise the boom arms 12, he moves the control lever 40 which, through an appropriate linkage, not shown, slides the spool 104 to the right as shown in FIGURE 4. If the control lever 40 is moved a suflicient amount, the detents 116 will engage the groove 112 and through the action of the spring 120 and the camrning surface 119 on the plunger 118, the valve spool 104 will be held in its raised position. That is, the valve spool 104, which is provided with land and grooves, not shown, to form a conventional open center neutral position valve will be held in a position such that hydraulic fluid under pressure will be directed through conduits, also not shown, to the head end of the lift cylinder 24 to raise the boom arms 12. As the boom arms 12 are raised the lug 94 will be rotated causing the arm 90 to rotate and, through the friction of the grommets 70, the

circular plate 86 will also be rotated. As the circular plate 86 rotates, the camming portion 88 will contact the roller 100 on the actuating arm 98. The camming portion 88 will pivot the arm 98 and actuate the valve 96 directing fluid under pressure through conduit 102 to the cylinder 124. The fluid pressure will force the captive piston 122 to the left as shown in FIGURE 4. The extension 126 will contact the plunger 118 forcing it, against the bias of spring 120, to the left also. This relieves the detents 116 of the force which retains them within the groove 112 and the spring 106 and the selfcentering sleeves 108 will return the valve spool 104 and control lever 40 to center neutral position. The flow of hydraulic fluid to the head end of the lift cylinders 24 will therefore be stopped and the boom arms 12 will be properly positioned.

It is often desirable or necessary for the operator to override the automatic control. As seen in FIGURE 4, a small additional force will be required on control lever 40 to move valve spool 104 against bias of detent spring 120 when valve 96 is open and piston 122 is exerting pressure against plunger 118 and it is desired to raise the boom arms 12 an additional amount. The valve 96 should be of the type which will vent, i.e., exhaust to atmosphere, the conduit 102 when valve 96 is in closed position (camming portion 88 beyond roller 100). When the conduit 102 is vented to the atmosphere, the pressure behind the piston 122 will be reduced to atmospheric pressure and the detents 116 will again become operative, permitting the operator to move the control valve spool 104 to the right so that detents 116 are engaged by the groove 112. Hydraulic fluid pressure will thereafter be provided to the head end of the cylinder 24 and move the boom arms 12 continuously until the lift cylinder 24 has reached the limit of its extension.

A lip or extension 69 may be provided on the plate 68, which lip or extension will extend beyond the periphcry of the circular plate 86. The placement of the ap propriate indicia, such as that shown by the numerals 1 through 7 in FIGURE 2, on the lip or extension 69 and the placement of an indicating mark 67 on circular plate 86 will permit the operator to quickly select that height to which he desires the bucket to be elevated. To select any given height then, the operator has merely to pull the knob 72 to the right as shown in FIGURE 3 and rotate the knob to align the appropriate indicia on the lip 69 so that it is opposite the indicating mark 67 on the circular plate 86.

It will be understood that various changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, maybe made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

1. An automatic boom positioning device for a tractor having a boom arm pivotally mounted thereon and a hydraulic lift cylinder for pivoting said boom arm, said tractor having a hydraulic system, including a control valve with a spool slidable between a neutral position and an operating position for controlling the flow of hydraulic fluid to said cylinder, said device comprising: a plate rotatably mounted on said tractor; cam means rotatably mounted on said tractor and positioned adjacent to said plate; drive means movable between a first position wherein said plate and said cam means rotate in unison and a second position wherein said cam means may be selectively rotated relative to said plate; link means connected between said plate and said boom arm for rotating said plate in response to pivotal movement of said boom arm; said control valve having a cylinder portion formed on one end thereof and a piston movable within said cylinder portion into contact with the spool whereby the spool is returned to the neutral position; and valve means operating responsive to rotation of the cam means to direct fluid under pressure to said cylinder portion and act on said piston to return said spool to the neutral position.

2. In a tractor loader having a boom arm pivotally mounted thereon and a hydraulic ram for pivoting said boom arm, said tractor having a hydraulic system including a control valve with a spool slidable between a neutral position and an operating position for directing hydraulic fluid under pressure to said ram, said device comprising a plate rotatably mounted on said tractor, cam means rotatably mounted on said tractor and positioned adjacent to said plate, drive means for rotating said plate and said cam means in unison, link means connected between said plate and said boom arm for rotating said plate in response to pivotal movement of said boom arm, valve means in operating engagement with the cam means, conduit means connected with said valve means, a source of fluid under pressure connected to and controlled by said valve means whereby said cam means operates said valve means to direct fluid under pressure through said conduit means, and release means to return said spool to the neutral position and terminate the pivotal movement of said boom arm responsive to fluid under pressure in the conduit means.

3. An automatic boom positioning device according to claim 2 wherein said drive means further comprises a friction member affixed to said plate, and bias means acting on said cam means for urging said cam means into engagement with said friction member, whereby said cam means may be moved against the force of said bias means away from said friction member and rotated relative thereto to adjust said cam means relative to said plate.

4. An automatic positioning device according to claim 3 and further comprising indicia on said plate, and an indicating mark on said cam means in juxtaposition to the indicia to permit selective adjustment of said cam means relative to said plate.

5. An automatic boompositioning device for use with a vehicle having a pivotal boom and power means to pivot the boom, the device comprising: first plate means mounted on the vehicle for rotation about an axis in response to pivotal movement of the boom; second plate means rotatably mounted on the vehicle about the axis in juxtaposition to the first plate means, the second plate means further being slidable to and from the first plate means along the axis; means to urge the second plate means into engagement with the first plate means to rotate both plate means together with a selected angular relationship therebetween, the second plate means being axially movable from the first plate means and rotatable about the axis to selectively vary the angular relationship; and,

means to inactivate the power means responsive to rotation of the second plate means to a predetermined location whereby the boom is automatically positioned with respect to the vehicle.

6. An automatic boom positioning device for use with a vehicle having a pivotal boom and hydraulic power means to pivot the boom, the device comprising: a plate element rotatably mounted on the vehicle; means to rotate the plate element in response to pivotal movement of the boom; a cam element mounted on the vehicle for rotational and axial movement with respect to the plate element; means to releasably urge the cam element against the plate element for rotation therewith whereby the cam element may be selectively moved in an axial direction from the plate element and rotated with respect thereto;

and, means to inactivate the power means responsive to rotation of the cam element to a preselected location for automatic positioning of the boom.

7. An automatic boom-positioning device for use with a vehicle having a pivotal boom and hydraulic power means to pivot the boom, the device comprising: a plate element mounted on the vehicle for rotation about a given axis; means to rotate the plate element in response to pivotal movement of the boom; a cam element on the vehicle mounted for rotational and axial movement with respect to the axis; biasing-means to resiliently urge the cam element into engagement with the plate element whereby the cam element normally rotates with a selective angular relationship with respect to the plate element, the cam element being selectively movable about the axis to vary the angular relationship; and means to inactivate the power means responsive to the rotation of the camming surface to a predetermined location.

References Cited by the Examiner UNITED STATES PATENTS HUGO O. SCHULZ, Primary Examiner. 

1. AN AUTOMATIC BOOM POSITIONING DEVICE FOR A TRACTOR HAVING A BOOM ARM PIVOTALLY MOUNTED THEREON AND A HYDRAULIC LIFT CYLINDER FOR PIVOTING SAID BOOM ARM, SAID TRACTOR HAVING A HYDRAULIC SYSTEM, INCLUDING A CONTROL VALVE WITH A SPOOL SLIDABLE BETWEEN A NEUTRAL POSITION AND AN OPERATING POSITION FOR CONTROLLING THE FLOW OF HYDRAULIC FLUID TO SAID CYLINDER, SAID DEVICE COMPRISING: A PLATE ROTATABLY MOUNTED ON SAID TRACTOR; CAM MEANS ROTATABLY MOUNTED ON SAID TRACTOR AND POSITIONED AJACENT TO SAID PLATE; DRIVE MEANS MOVABLE BETWEEN A FIRST POSITION WHEREIN SAID PLATE AND SAID CAM MEANS ROTATE IN UNISON AND A SECOND POSITION WHEREIN SAID CAM MEANS MAY BE SELECTIVELY ROTATED RELATIVE TO SAID PLATE; LINK MEANS CONNECTED BETWEEN SAID PLATE AND SAID BOOM ARM, FOR ROTATING SAID PLATE IN RESPONSE TO PIVOTAL MOVEMENT OF SAID BOOM ARM; SAID CONTROL VALVE HAVING A CYLINDER PORTION FORMED ON ONE END THEREOF AND A PISTON MOVABLE WITHIN SAID CYLINDER PORTION INTO CONTACT WITH THE SPOOL WHEREBY THE SPOOL IS RETURNED TO THE NEUTRAL POSITION; AND VALVE MEANS OPERATING RESPONSIVE TO ROTATION OF THE CAM MEANS TO DIRECT FLUID UNDER PRESSURE TO SAID CYLINDER PORTION AND ACT ON SAID PISTON TO RETURN SAID SPOOL TO THE NEUTRAL POSITION. 